Apparatus for collecting precious metals.



L. B. GRAY.

APPARATUS FOR COLLECTING PRECIOUS METALS.

APPLIOATION FILED AUG. 29, 1910. RENEWED AUG. 22, 1912.

Patented Mar. 18, 1913.

UNITED STATES PATENT OFFICE LAWRENCE B. GRAY, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO HYDRAULIC VACUUM DREDGING COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

APPARATUS FOR COLLECTING PRECIOUS METALS.

Application filed August 29, 1910, Serial No. 579,410. Renewed August 22. 1912.

To all whom it may concern:

Be it known that. I, LAWRENCE BI GRAY.

of Boston. in the county of Suffolk and State of I\Iassachusetts, have invented certain new and useful Improvements in Apparatus for Collecting Precious Metals, of which the following is a specification. This apparatus relates to placer mining, and has for its object to collectthe gold or other precious metals or stones found mingled with sand, gravel. dirtand other rela tively valueless material, from which it is separated by washing.

The general object is the retensiom and saving of all gold which is being separated from the base material by washing. and the particular object by which the ends of the 'main object are served is to enable the nonamalgamating as well as the amalgamating gold or other precious metal to be retained and saved.'

As is well known, the simplest and most commonly used method of collecting the gold which is found in a free state mingled with base material and separated therefrom by washing. is to amalgamate the gold by carrying it in contact with mercury. Some gold, however, will not amalgamate, owing either to the fact that it is-coated with some material which prevents the mercury from acting upon it. or that it is combined with other elements, or from other causes.

The object of the present invention. therefore. is to provide a means by which the nonamalgamat-ing gold may be withdrawn from the stream. which washes it. In carrying this object into practical effect, I make use of the fact that the specific gravity of gold is much greater than that of the material in company with which it is found. and upon the further wellknown fact which results from this characteristic, that when gold is once thrown down by centrifugal action from the stream which carries it, it will. not again be picked up by the stream.

The means by which I make practically efi'ective the above objects, and one of the many possible forms of apparatus in which the principles of my invention may be embodied, is shown in the accompanying drawings, in which,

Figure 1 represents a side elevation of. the apparatus. Fig. 2 represents a longitudinal section of thesame. Fig. 3 represents a plan wall of the Specification'of Letters Patent. 1 Pafehted DIar, 18, 1913.

Serial No. 716,563.

Fig. 1.

The same reference characters indicate the same parts in all the figures.

In the following description I shall principally-refer to the precious metal which is collected by the means described, as gold, this being because gold is the metal most commonly collected in this manner, and also. for convenience and' brevity of description. I desire at the outset,'however, to make it distinctly understood thatI do not limit myself to gold as the metal capable of collection by this apparatus, but that I propose to'use it in connection with any metal or precious stones having a suflicient-ly high specific gravity for the purpose, as hereinafter appears.- Hence it is to be understood that wherever the word gold appears in the specification or claims, I have in mind and intend to refer to any substance which, when acted upon, isnot cohesively joined with the 1 other materials among which it occurs, and which has a sufii'ciently greater specific gravity than the materials with which it is mingled to act in the manner hereinafter described.

The apparatus consists in the first place in a sluice or fiume a, which serves as a conduit for leading a flowing stream used in washing the gold or other metal to be collected from the materials with which it is mingled. In the bottom of thesluice is contained a pocket or chamber 6 of peculiar form, designed to give a whirling motion to the water which enters it, and thereby cause the heavy solids'carried by the water to be thrown out and down, while the lighter solids continue with the stream 'outof and beyond the pocket. For this purpose the bottom of the sluice is somewhat elevated on a gradual slant, as shown at c, reaching its highest elevation at the point where the rear pocket commences. It should be noted that the flow of the stream is supposed to be from left to right with reference to the drawings. The flowing stream and solid matter carried. by it thus-enter the pocket and strike the farther wall 1) thereof. This wall is curved and extends downwardly and back oppositely to the direction of flow of the stream. In the bottom of the pocket is formed a narrow recess (1, the walls of which extending partof the pocket wall I) on a smooth curve of sharp radius. For convenience of construction'the pocket I) with its bottom recess (1 and rib e is formed in a metal piece, which is inlaid into the bottom of the sluice, the latter bein ordinarily of wood. The pocket may be built directly into the sluice, however, and would ordinarily be so if some such material-as concrete were used for the'construction of the sluice. The pocket extends entirely across the sluice from one side to the other, and at one end, in line with its bottom recess (Z and outside of the sluice, it has a cap f. which isremovable to permit the collected gold to be withdrawn. I

Above the pocket is a baflle g, which is adjust-ably hung upon studs h extending across the top ofthe sluice. The baflle has at its ends flanges 2' provided with slotsj through which the studs h pass. It is adjustable about the studs and is retained at various angles by a pin lgfwhich is adapted to be passed through any one of a number of holes 7 in platesvm which secure the studs 72,, these holes being arranged angnlarly around the apertures which contain the studs 71. The

frictional clamping means for securing the bafile is found in the heads 71' of the studs h which press the flanges 11 against the plates m when drawn outwardly by the nuts h which are threaded on the outer ends ofthe= studs. The baflle may be set at'various angles with respect to the flowing stream. and may be made to extend to grea er or less depths below the surface thereof, according as best serves the purpose of producing eddies in the water, causing it to. enterv the pocket. The plates m rest on the walls of the s'luice and have flanges m which lie against the sides of these walls as shown in Figs. 1 and 4. They are secured together by bars 7), as shown in Fig. 3, which form with the plates a frame carrying the baflle. As this frame rests on the sluice walls (as shown) being unconfined except by the flanges m, it may be moved along the sluice I to placethe baifle at anypositlon desired with respect to the pocket, so that when the I angular adjustments above described are made, the bottom edge of the baffle may be in the best position for securing the. esired eflects.

When the stream flowing through the sluice encounters the bafile, it is checked and eddies are set. up which cause the solid matter to be carried into the pocket with a portion of the water. This checking of the water also causes an additional head to accumulate in front of the baffle, and the restriction of the passage through which the water may flow causes-together with the accumulation of head, a greater force of [low of the water through the narrow space below the batlie. This 'baflle is an important feature of the invention, as it causes the water to move with suflicicnt force, and particularly to have such directions of movement as to wash the gravel out of the pocket as well as into it. The rapid changes in direction of the material flowing through the pocket causes the heavy material to be thrown outward by centrifugal force, and as the gold is the heaviest of all the materials propelled'by the water. it finds its way to the wall of the pocket, crowding back the lighter solids and entering the recess (Z. If any gold carried by the water travels as far as the rib c, it is thrown down by its own momentum into the recess d when the water passes upward around the rib. I have found that this device is efi'ective for entrapping all of the gold which is heavy enough and in large enough particles to sink in the water. At the same time that the gold is caught, the sand and mud are carried out from the pocket with the outflowing water and across the stream entering the pocket. The reason that -the sand. etc. is carried out of the pocket and leaves the gold behind is that gold which has once been precipitated upon the bottom of a flowing stream will not be again picked up by the water. but will remain on the bottom. while lighter solids. like pieces of stone are picked up and carried great distances by the stream. The abrupt walls of the recess (Z in the bottom of which the gold collects. also assist'greatlv in reventing the gold from being removed by the impact of other floating particles.

n the bottom of the sluice is ano her pocket or receptacle 7) for collecting the gold which is in s h a condition that it will amalgamate. This pocket ma be arranged either in advance of or in rear of the pocket 7) as may be desired. Tn 79 is located a quantitv of ouick silver. which rises nearlv to the top of the pocket. The bottom of the sluice is inclined unwardlv. somewhat as shown at- 79' in front of the pocket. so as to retard the gold. etc.. and assist in precipitating it into the pocket. The sold will sink in the quick silver while the sand. mud and stones will float on its surface and be washed away bv the water. At the ends thelower part of the pocket is formed with tubular nipples I] which extend beyond the sides of the sluice and are closed by detachable caps 1- which can be removed to withdraw the amalgam.

1 The combination of a sluice through which a stream of water carrying minerals is caused to flow, with a pocket element in the bottom of the sluice,'said pocket element having wall farthest from the feed of,

"entrance end of the sluice spirally curved downwardly, reversely with respect to the stream flow, upwardly beneath the bottom of the sluice, andagain downwardly, whereby a whirling motion is given to the portion thrown to the bottom of the-stream which enters the pocket and the materials of greatset specific gravity are thrown to the bottom of the pocket.

2.The combination of a sluice through which a stream of waterca-rrying minerals is caused to flow, witlra pocket- .element in the bottom of the sluice, said pocketelement having its wall farthest from the feed or entrance end of the sluice spirally curved downwardly, reversely withv respectto the stream flow, upwardly beneath the bottom of the sluice, and again downwardly, and

ha 'ing a' recess in its bottom, whereby a whirling-motion'is given to the "portion ofthe stream which enters the pocket and the materials of greatest sp ific gravity are f the pocket and caused to lodge in said recess. v

3. The combination of a sluic'e through which a stream of water carrying 'minerals' is caused to flow, with a pocket element in the bottom of'the sluice, said pocket element having its wall farthest from the feed aor.

entrance end of the sluice elevated above the rest of the pocket and presenting a sharp angle to. the stream, adapting it to deflect the lower stratum, said wall being spirally curved downwardly, reversely with respect to the stream flow, upwardly beneath the v bottom of the sluice, and again downwardly,

whereby a whirling motion is given to the portion of the stream which enters the pocket and the materials of greatest specific gravity are thrown to' the bottom of the pocket. i 4. I11 combination, a sluice and a deflector, said deflector consisting of a bafiie,plates supported on the walls of the sluice and adjustable longitudinally thereof, alined,horizontal pivots connecting said battle with the respective plates, whereby the inclination of the baflle with respect to the stream flow 5. The combination with a sluice having upright side walls, of an adjustable deflector, comprising 5 plates mounted and longitudinally'slida'ble onthe walls of the sluice and provided with flanges overlying the sides of such-walls to retain them thereon, orizontal piv'ot studs in the respective plates, a-

baflie betweensaid plates having slotted flanges at 1ts ends bent at right angles to the plane of the baflle and lying close to the plates throu h which said studs pass, whereby the baflie is adjustable both angularly-and as to height, .and' clamping nuts on the studs for binding the flangesagainst the plates.

In testimony whereof I have afiiried my 'signature,'-in presence of two witnesses, I LAWRENCE B. GRAY. \Vitnesses: J i v i A. H. BROWN,

P. Pnzzn'r'rr, 

